For Faculty & Staff

Contact

Search SF State News

Search SF State News

Refining the search for new
planets

February 2,
2009 -- SF
State's planet hunting team is trying new avenues of investigation in
the quest to discover planets beyond our solar system. At the American
Astronomical Society (AAS) meeting in January, graduate students presented
novel approaches being used by the Exoplanet Group to search for earth-like
planets.

While the search for planets has typically focused on solar-type stars,
the Exoplanet Group has begun a new project observing red dwarf stars.
Astronomy student Kelsey Clubb shared a poster presentation at the AAS
meeting explaining why these cool, low-mass red dwarfs make promising
targets.

"We believe that focusing on low-mass stars will lead to the detection
of more smaller-mass planets similar to the Earth, and planets with liquid
water and temperatures that could sustain life," Clubb said.

Red dwarfs are so faint that they are invisible to the naked eye. However,
they are highly suitable for indirect observations because planets orbiting
red dwarfs produce a bigger wobble in the host star. Astronomers can
detect planets by measuring the gravitational tug that planets exert
on their host star, producing a wobble in the star's rotation.

Previous studies of low mass, red dwarf stars show that they are more
likely to be accompanied by low mass planets. Since the project began
last September the team has identified five red dwarf stars that are
prime candidates for further investigation.

Astronomy student Howard Isaacson shared a presentation at the AAS meeting,
explaining how his work on stellar activity is aiding planet search efforts. "There
can be all kinds of activity in a star's atmosphere such as explosions,
flares and solar winds," Isaacson said. "This 'activity' can
cause changes in a star's luminosity which could be mistakenly interpreted
to indicate the presence of an orbiting planet."

"Howard's work is fundamental to our search for exoplanets because
stars that have high activity levels are too 'noisy' for planet searches," said
Assistant Professor of Astronomy Debra Fischer, who leads SF State's
Exoplanet Group.

A screen shot of software designed by SF State researchers
to help model multiple planet systems.

At a professional booth hosted by NASA and the Jet Propulsion Laboratory
at the AAS meeting, SF State researchers were invited to present a demo
version of their planet detection software along with a newly-designed
graphical user interface. The graphical user interface (GUI) allows users
to analyze data collected from observations of stars to model multiple
planet systems.

"Users can enter parameters about their planet search data such
as mass and orbital period and they can then see a simple visual simulation
of the multiple planet system on the screen," said Julien Spronck,
a postdoctoral fellow who worked on the GUI with astronomy students John
Brewer and Matt Giguere. "This is a convenient way for people to
model multiple planet systems without having to think about the complicated
mathematical equations behind the model," Spronck said. The software
can manipulate radial velocity data, which measures changes in the star's
speed, as well as astrometric data which measures changes in the position
of the star.

"The process of fitting data and detecting planets has often been
in the hands of a few people in the world," Fischer said. "This
software is exciting because it makes it possible for other people to
quickly understand the process."